Sökning: "dielectric strength"

Visar resultat 1 - 5 av 42 avhandlingar innehållade orden dielectric strength.

1. 1. Charge Accumulation in Hybrid High Voltage Insulation

   Författare :Mats Sjöberg; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; dielectric barrier; charge accumulation; high voltage; dielectric barrier discharge; dielectric coating; hybrid insulation; electric field distribution; discharge modelling; breakdown strength; charge conditioning;

   Sammanfattning : This thesis deals with the novel idea of controlling the electric stress or field distribution in a hybrid air - solid-dielectric high voltage insulation by promoting accumulation of surface charges on the internal interfacial layers in the combined (hybrid) dielectric structure. Primarily, applications are expected to be found in high voltage dc systems and as a method to improve the resistance against insulation failure by overvoltages, e. LÄS MER

3. 2. Cellulose-based electrical insulation materials : Dielectric and mechanical properties

   Författare :Rebecca Hollertz; Lars Wågberg; Markus Biesalski; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; cellulose; dielectric materials; electrical insulation; nanocellulose; nanoparticles; streamer; Fiber- och polymervetenskap; Fibre and Polymer Science;

   Sammanfattning : The reliability of the generation and distribution of electricity is highly dependent on electrical insulation and is essential for the prosperity of our society and a ubiquitous part of our everyday life. The present study shows how some important material properties affect the electrical properties of cellulose-based electrical insulation systems which are used together with mineral oil in high-voltage transformers. LÄS MER

4. 3. Electrical Insulating Properties of Poly(Ethylene-co-Butyl Acrylate) Filled with Alumina Nanoparticles

   Författare :Nadejda Jäverberg; Hans Edin; John Fothergill; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; nanocomposites; poly ethylene-co-butyl acrylate ; EBA; alumina; dielectric permittivity; absorbed water; humidity; temperature; dielectric spectroscopy; breakdown strength; pre-breakdown current;

   Sammanfattning : In this work the electrical insulating properties of the nanocomposite materials based on poly(ethylene-co-butyl acrylate) filled with alumina nanoparticles are studied. The dielectric properties chosen for the evaluation are the dielectric permittivity and loss as well as the breakdown strength and the pre-breakdown currents. LÄS MER

5. 4. Assessment of ceramic raw materials in Uganda for electrical porcelain

   Författare :Peter Wilberforce Olupot; Stefan Jonsson; Thommy Ekström; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; porcelain; characterisation; bending strength; dielectric strength; Uganda; Chemical engineering; Kemiteknik;

   Sammanfattning : Clay, quartz and feldspar are widely available in Uganda. The location and properties of various clay deposits are reported in the literature, but little is reported on feldspar and quartz deposits. In this work an extended literature on ceramics and porcelains in particular, is documented. LÄS MER

7. 5. Acetylation of Solid Wood. Wood Properties and Process Development

   Författare :Pia Larsson Brelid; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; microwave heating; deformation; wood; hardness; adhesive bonding; power penetration depth; shear strength; delamination; acetylation; pH; bending strength; dielectric properties; stability;

   Sammanfattning : The influence of acetylation on selected wood properties has been determined for Scandinavian pine and spruce wood, in order to predict the behavior of acetylated wood when it is used in different applications. Only minor differences in both bending strength and the modulus of elasticity were obtained for acetylated wood when compared with unmodified wood, and can, for practical applications, be considered unaltered. LÄS MER